For fire safety purpose, many optical fiber modules are subjected to various fire safety standards. For example, dispersion slope compensating modules (DSCM) are required to include fire resistant materials rated V-1 or better as determined by Underwriters Laboratories Standard 94 (UL94). However, common fiber coatings do not satisfy the requirement. On the contrary, most commonly used primary and secondary coatings for optical fibers burn rapidly.
The traditional way to satisfy this fire safety requirement has been to encapsulate the dispersion compensating fiber into a package made by steel or aluminum to make a DSCM. Examples of such DSCMs are disclosed in U.S. Pat. No. 6,456,773 and U.S. Pat. No. 6,996,322. Many manufacturers encapsulated the dispersion compensating fiber in a DSCM with a steel or aluminum package to pass a required fire spread test(s). One example of such test is called Equipment Assembly Fire Spread Test. This test is in accordance with Telcordia GR-63-CORE, Sec. 5.2. It characterizes the fire propagation hazard, and demonstrates that fire from an equipment assembly does not spread beyond the structural elements of the equipment under the test. Such test is performed to make sure that the DSCM would neither burn nor add fuel to an ongoing fire in, for example, a central office rack.
However, the metal cover on a DSCM adds additional process steps in production and increase the product cost. Therefore, there is a need for an optical fiber module, which satisfies required fire safety test(s) without the need of a metal cover.